首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2387篇
  免费   96篇
  国内免费   14篇
耳鼻咽喉   47篇
儿科学   102篇
妇产科学   196篇
基础医学   190篇
口腔科学   109篇
临床医学   211篇
内科学   626篇
皮肤病学   26篇
神经病学   114篇
特种医学   92篇
外科学   454篇
综合类   46篇
预防医学   66篇
眼科学   65篇
药学   81篇
中国医学   5篇
肿瘤学   67篇
  2023年   10篇
  2022年   23篇
  2021年   39篇
  2020年   29篇
  2019年   38篇
  2018年   55篇
  2017年   50篇
  2016年   78篇
  2015年   88篇
  2014年   97篇
  2013年   145篇
  2012年   224篇
  2011年   197篇
  2010年   114篇
  2009年   119篇
  2008年   163篇
  2007年   177篇
  2006年   153篇
  2005年   163篇
  2004年   138篇
  2003年   115篇
  2002年   81篇
  2001年   68篇
  2000年   41篇
  1999年   43篇
  1998年   9篇
  1997年   7篇
  1996年   5篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   4篇
  1991年   5篇
  1990年   3篇
  1989年   4篇
  1988年   1篇
  1986年   2篇
  1984年   1篇
  1983年   2篇
  1973年   1篇
排序方式: 共有2497条查询结果,搜索用时 26 毫秒
51.
52.
OBJECTIVE: Regular physical activity is associated with decreased morbidity and mortality. Traditionally, patients with rheumatoid arthritis (RA) have been advised to limit physical exercise. We studied the prevalence of physical activity and associations with demographic and disease-related variables in patients with RA from 21 countries. METHODS: The Questionnaires in Standard Monitoring of Patients with Rheumatoid Arthritis (QUEST-RA) is a cross-sectional study that includes a self-report questionnaire and clinical assessment of nonselected consecutive outpatients with RA who are receiving usual clinical care. Frequency of physical exercise (>or=30 minutes with at least some shortness of breath, sweating) is queried with 4 response options: >or=3 times weekly, 1-2 times weekly, 1-2 times monthly, and no exercise. RESULTS: Between January 2005 and April 2007, a total of 5,235 patients from 58 sites in 21 countries were enrolled in QUEST-RA: 79% were women, >90% were white, mean age was 57 years, and mean disease duration was 11.6 years. Only 13.8% of all patients reported physical exercise>or=3 times weekly. The majority of the patients were physically inactive with no regular weekly exercise: >80% in 7 countries, 60-80% in 12 countries, and 45% and 29% in 2 countries, respectively. Physical inactivity was associated with female sex, older age, lower education, obesity, comorbidity, low functional capacity, and higher levels of disease activity, pain, and fatigue. CONCLUSION: In many countries, a low proportion of patients with RA exercise. These data may alert rheumatologists to motivate their patients to increase physical activity levels.  相似文献   
53.
54.

Background and Objectives:

Prostate cancer and inguinal hernia are common health issues in men aged more than 50 years. Recently, more data are accumulating that laparoscopic radical prostatectomy (LRP) and laparoscopic inguinal hernia repair (LIHR) can be performed in the same operation. The purpose of this study was to compare patients who underwent simultaneous extraperitoneal LRP (E-LRP) and LIHR with control patients who underwent only E-LRP in a matched-pairs design.

Methods:

Medical records of 215 patients were evaluated, and 20 patients who underwent E-LRP+LIHR were compared with 40 patients who underwent only E-LRP in a matched-pairs analysis. Preoperative clinical parameters (age, body mass index, prostate-specific antigen, clinical stage, Gleason score of the prostate biopsy, and prostate volume) and operative data (operation time, duration of catheterization, length of hospital stay, estimated blood loss, time to perform the anastomosis and its quality, and the percentage of patients with bilateral lymphadenectomy) were evaluated, as well as postoperative parameters (pathological stage, Gleason score, specimen weight, follow-up duration, biochemical recurrence, complication rates, and duration of postoperative analgesic treatment).

Results:

No statistically significant differences were found in the preoperative and operative parameters between the 2 study groups. Pathological parameters and the follow-up period and complication rates were similar between the 2 groups.

Conclusion:

Performing LIHR and E-LRP during the same operation is safe and feasible in the treatment of patients with prostate cancer and inguinal hernia.  相似文献   
55.
BACKGROUND: Elevated C-reactive protein (CRP) has been found to correlate with higher risk for cardiac events in patients with acute myocardial infarction (AMI). It has been suggested that CRP may be involved in initiation process of coagulation; however, the role of CRP level in the formation of left ventricular (LV) thrombus has not been studied. HYPOTHESIS: This study investigated whether CRP is a risk factor for LV thrombus in patients with AMI. METHODS: Clinical, echocardiographic, and biochemical data were analyzed in 141 consecutive patients (aged 57 +/- 13 years; 33 women) with first anterior AMI. Two-dimensional and Doppler echocardiographic examinations were performed on Days 1, 3, 7, 15, and 30. Blood samples were obtained every day during hospitalization. Serum CRP concentrations were measured by an ultrasensitive immunonephelometry method. RESULTS: Left ventricular thrombus was detected in 33 (23.4%) patients. Univariate analysis showed that patients with LV thrombus had a higher peak creatine kinase (CK) level (2,879 +/- 742 vs. 1,693 +/- 1,210 I/U, p = 0.001), higher peak CRP level (14.9 +/- 7.1 vs. 9.2 +/- 6.8 mg/dl, p = 0.001), higher wall motion score index (1.8 +/- 0.2 vs. 1.5 +/- 0.3, p = 0.002), higher apical wall motion score index (2.35 +/- 0.72 vs. 2.07 +/- 0.70, p = 0.001), larger end-diastolic volume (145.2 +/- 43.7 vs. 116.5 +/- 44.2 ml, p = 0.002), larger end-systolic volume (85.4 +/- 37.2 vs. 62.9 +/- 31.6 ml, p = 0.003), and lower ejection fraction (42.1 +/- 12 vs. 47.3 +/- 13, p = 0.04). In multivariate analyses, only peak CK level (p = 0.0001), LV apical wall motion score index (p = 0.001), and CRP levels (p = 0.001) were independent predictors of LV thrombus formation. CONCLUSIONS: These results suggest that CRP is a risk factor for LV thrombus in patients with AMI.  相似文献   
56.
Molecular mechanisms contributing to the tumorigenesis of pancreatic endocrine tumors (PETs) are still not well understood. Allelic deletions at chromosome 22q12.3 were detected in about 30-60% of PETs, suggesting that inactivation of one or more tumor suppressor genes on this chromosomal arm is important for their pathogenesis. Because the putative tumor suppressor gene tissue inhibitor of metalloproteinase-3 (TIMP-3) has been located at 22q12.3, we undertook a genetic analysis of TIMP-3 to determine its role in the tumorigenesis of PETs. Single-strand conformational polymorphism analysis, methylation-specific PCR, RNA expression analysis, and immunohistochemistry of TIMP-3 were performed in 21 sporadic PETs. Thirteen of 21 PETs (62%) revealed TIMP-3 alterations, including promoter hypermethylation and homozygous deletion. The predominant TIMP-3 alteration was promoter hypermethylation, identified in 8 of 18 (44%) PETs. It was tumor-specific and corresponded to loss or strong reduction of TIMP-3 protein expression. Notably, 11 of 14 (79%) PETs with metastases had TIMP-3 alterations, compared with only 1 of 7 (14%) PETs without metastases (P < 0.02). These data suggest a possibly important role of TIMP-3 in the tumorigenesis of human PETs, especially in the development of metastases, which has to be further evaluated in large-scale studies.  相似文献   
57.
ObjectiveThe aim was to compare coronary high-definition CT (HDCT) with standard-definition CT (SDCT) angiography as to radiation dose, image quality and accuracy.ResultsThe intraclass correlation coefficient (ICC) of measured vessel attenuation values in SDCT between the two radiologists was exceedingly good. The ICC was higher in HDCT. The radiation dose of HDCT was higher than that of SDCT. The mean tube current was 180 (mA) in HDCT and 147(mA) in SDCT with the same tube voltage (kVp). There was no significant difference between image quality.ConclusionHDCT has a higher radiation dose but has much more atenuation and the spatial resolution which improve measurement accuracy for imaging coronary arteries.  相似文献   
58.
[Purpose] To assess the effects of different numbers of platelet-rich plasma (PRP) applications on pain and physical function in grade 3 knee osteoarthritis (OA). [Subjects and Methods] A total of 102 patients with grade 3 knee OA were randomly divided into three groups: Group 1 received a single injection of PRP, Group 2 received two injections of PRP two weeks apart, Group 3 received three injections of PRP at 2-weeks intervals. All patients were evaluated with a visual analog scale (VAS), the Western Ontario and McMaster Universities Arthritis Index (WOMAC), and the Timed-Up and Go test (TUG) before the treatment and at 1, 3 and 6 months after the treatment. [Results] Ninety-eight patients (15 males, 83 females) completed the study. The mean ages of the patients were 53.5±6.6, 54.9±5.3, and 55.1±5.6 years in Group 1, Group 2, and Group 3, respectively. Statistically significant improvements were noted in all of the evaluated measures in all of the groups. The mean differences of Group 1-Group 2 and Group 1-Group 3 WOMAC total, WOMAC pain, WOMAC stiffness, and WOMAC function scores were statistically significant. [Conclusion] PRP is an effective treatment for functional status and pain in moderate knee osteoarthritis and a minimum of two injections is appropriate.Key words: Platelet-rich plasma effectiveness, Moderate, Knee osteoarthritis  相似文献   
59.
The cranio-orbital foramen (COF) is located on the lateral wall of the orbit. It is a potential source of hemorrhage during deep lateral orbital dissection, since it functions as an anastomosis between the lacrimal artery and the middle meningeal artery. The aim of this study was to guide and facilitate the surgical procedures in the orbit, so as to determine a navigational area and the precise location of the COF and to standardize certain anatomical marks. The navigational area of the COF and topographical features were studied in 75 craniums with presented COF. 33 bilateral main COFs, 41 (18 on the right, 23 on the left) unilateral main COFs at the main cranium and 19 accessory COFs were studied for their navigational features on the orbit. The distances between the COF and the fronto-zygomatic suture, supraorbital notch, lateral angle of the superior orbital fissure (SOF) and Whitnall’s tubercle were measured. The mean distance of the COF from the fronto-zygomatic suture, supraorbital notch, lateral angle of the SOF and Whitnall’s tubercle was 26.3, 37.3, 92 and 27.1 mm, respectively. For the navigational area signs of the COF, areas of the orbit that form the transversal and vertical lines are generated on the reference points. Whilst the upper outer area of the orbit contains a potential bleeding risk, the bottom section of the outer column is identified as safe for the surgical operations of the lateral orbital wall. The fronto-zygomatic suture and Whitnall’s tubercle are recommended as the most reliable navigational landmarks for identifying the COF. Hence, the transversal and vertical orientation of the COF should be mastered by the surgeons reconstructing the anterior base of the skull and the orbit.  相似文献   
60.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号